Re: User concurrency thresholding: where do I look?

From: "Simon Riggs" <simon(at)2ndquadrant(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Jignesh K(dot) Shah" <J(dot)K(dot)Shah(at)Sun(dot)COM>, "Josh Berkus" <josh(at)agliodbs(dot)com>, <pgsql-performance(at)postgresql(dot)org>, "Alvaro Herrera" <alvherre(at)commandprompt(dot)com>
Subject: Re: User concurrency thresholding: where do I look?
Date: 2007-07-23 15:47:43
Message-ID: 1185205663.4284.249.camel@ebony.site
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On Mon, 2007-07-23 at 10:54 -0400, Tom Lane wrote:
> "Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> > I looked at this last May and my notes say "ExecutorState". I guess that
> > was wrong, but my analysis showed there was a single malloc of 8228
> > bytes happening once per query during my tests.
>
> Well, if you can track down where it's coming from, we could certainly
> hack the containing context's parameters. But EState's not it.

Well, I discover there is an allocation of 8232 (inflation...) made once
per statement by a memory context called... ExecutorState. Still not
sure exactly which allocation this is, but its definitely once per
statement on pgbench, which should narrow it down. Plan, query etc?

I don't see a way to hack the allocation, since the max chunk size is
8K.

--
Simon Riggs
EnterpriseDB http://www.enterprisedb.com

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